Abstract: Apparatus for monitoring fetal health during labor detects the occurrence of a fetal ECG in digital signals derived from electrodes on a fetus using a matched filter routine to detect a QRS complex. The peaks of successive R waves are then found and used to determine fetal heart rate. After time coherent filtering of digital samples representing the fetal ECG the P-R interval and the elevation of the S-T interval are found and a correlation coefficient between the fetal heart rate and the P-R interval is derived. The elevation and the coefficient are displayed. If the correlation coefficient becomes positive for about half an hour and a significant fall in the elevation of the S-T interval also occurs it is an indication of acidosis of the fetus.